Symptoms include
Small size, with a disproportionately large head
Sharper looking, less rounded features than a full-term baby's features, due to a lack of fat stores
Fine hair (lanugo) covering much of the body
Low body temperature, especially immediately after birth in the delivery room, due to a lack of stored body fat
Labored breathing or respiratory distress
Lack of reflexes for sucking and swallowing, leading to feeding difficulties